The present invention relates to a control valve assembly for spray guns wherein a water-pressure adjusting valve is situated between a stop seat of a valve chamber and a top-support portion of a valve seat so as to buffer the water pressure generated at the instant of water discharge and maintain the balance of water pressure within the valve chamber thereof; besides, a flexible valve is equipped with a support surface and a pivoting rod respectively squeezed and abutted tight by a guide-and-push surface and a positioning ring of a pressure valve so that a control button can precisely control the discharge or shutoff of water supply, facilitating more smooth and accurate operation thereby.
A conventional spray gun (as shown in the attached document) is disclosed in the Taiwan Patent titled “Spray Gun Control Valve Assembly Structure” filed on Jun. 27, 2005 with an application No. 94210790 and granted for publication on Dec. 1, 2005 by No. M 281720. However, this prior art contains some disadvantages. Most of all, when a control button 25 of a spray gun body 20 is pushed downwards, water supply will immediately flow from a first aperture 211 to pass through a port 37 of an end cover 30 and water intake spaces 743 of a collar 74 for discharge in an instant. Meanwhile, a water-sealing portion 72 of a flexible valve 70 has already detached from the close abutment of a push guiding surface 53 of a pressure valve, and water pressure generated in the moment of water discharge tends to squeeze at the water-sealing portion 72 of the flexible valve 70 and deform it thereby. Besides, the pressure generated instantly by the water discharge can overpower the elastic force of a spring 36 and hinder the operation of a valve sleeve 40 and the pressure valve in return back to the state of water shutoff. Therefore, the control button 25 becomes hard to push and fails to provide an accurate control of water discharge or shutoff in operation thereof.